全球智库信息集成服务系统

Tropical tree species are divided into two principal groups, climax (or shade-tolerant)
and pioneer (or light demanding) tree species. The top canopy leaves of mature trees
are exposed to high solar radiation, regardless of whether they are climax or pioneer
trees. This article compares leaf physiology and morphology at the top canopies of a
climax Dipterocarpus corunutus tree and a pioneer Macaranga gigantea tree in a
rainforest, East Kalimantan. Their data indicate low light-use capacity and high
susceptibility for excess light energy of photosystem II in D. cornutus. The leaf
properties were different between the mature climax and pioneer trees, even if their
leaves grew under similar light environments at the top canopies.